Store dict in match field if empty

core/lib/rules.py

@@ -159,6 +159,8 @@ class NotificationRuleData(object):
         Get a match result for an index.
         """
         if self.object.match is None:
+            self.object.match = {}
+            self.object.save()
             return None
         if not isinstance(self.object.match, dict):
             return None